I have a ZEISS Conquest HD-5, 5-25X50mm main tube is a 1 inches, it is on a Browning Éclipse M-1000 with a bull barrel and the BOSS system, in 300 WSM, this scope Aldo it is a 1 inche tube is really accurate and hold it adjustment, shot a big black bear I aimed for the carotide/jugular complex...